Skip to content
My WebMD Sign In, Sign Up

Allergies Health Center

Select An Article
Font Size

Blood Testing for Allergies

(continued)

Allergy Blood Test Results

A positive result means allergy-specific antibodies were detected in your blood. This is usually a sign of an allergy.

The blood test will reveal what exactly you are allergic to. However, you can test positive for something but never have had an allergic reaction to it.

A negative result means you probably do not have a true allergy. That means your immune system probably does not respond to the allergen tested. However, it is possible to have a normal (negative) allergy blood test result and still have an allergy.

Allergy blood test results should be interpreted with caution by an allergy specialist. Your doctor will also consider your symptoms and medical history when diagnosing a specific allergy.

Side Effects of Allergy Blood Tests

Allergy blood testing is relatively safe. Side effects are usually minor and may include:

  • Swelling and redness at the site where the needle was inserted
  • Pain
  • Bleeding at the site where the needle was inserted
  • Some people may faint during blood testing.
1|2

WebMD Medical Reference

Reviewed by Melinda Ratini, DO, MS on November 19, 2013
Next Article:

Today on WebMD

man blowing nose
Make these tweaks to your diet, home, and lifestyle.
Allergy capsule
Breathe easier with these products.
 
cat on couch
Live in harmony with your cat or dog.
Woman sneezing with tissue in meadow
Which ones affect you?
 

woman sneezing
Slideshow
Bottle of allergy capsules and daisies
Article
 
Urban blossoms
Slideshow
Woman blowing nose
Slideshow
 

Woman with itchy watery eyes
Slideshow
Allergy prick test
VIDEO
 
Man sneezing into tissue
Tools
woman with duster crinkling nose
Quiz